I've shot vanes for YEARS!!! Back in the 1980's it was HARD to find store bought arrows fletched with feathers...
All of us boys shot recurves and aluminium arrows fletched with plastic vanes. The key to good arrow flight was a rubber Bear "weather-rest"... It worked like a charm!!!
Now days, all of the compound shooters use differant style rests and shoot "cock vane down". It is almost IMPOSSIBLE to find store bought arrows that are fletched "conventionaly" (cock vane out) BUT, This is a GOOD thing for us!!!!!
Go to the store,and buy a 1/2 dozen aluminium or carbon arrows that are fletched "cock down" and correctly spined for your bow. Nock the arrow so that the cock vane is up and in line with your string. Shoot them a few times and you will be GREATLY supprized!!!!! You may need to raise your nock point alittle (1/4") and play with the brace hieght to "fine tune" things,but I'm sure you'll be VERY pleased with the arrow flight.